JP4527497B2 - Chain tensioner - Google Patents

Description

  The present invention relates to a chain transmission device, and more particularly to a chain tensioner that maintains a constant chain tension of a chain transmission device for driving a camshaft.

  As a chain tensioner that keeps the chain tension of the camshaft drive chain transmission device constant, a plunger and a spring that presses the plunger outward are incorporated in a cylinder chamber formed in the housing. Conventionally known is an oil supply passage that communicates with the pressure chamber formed on the back of the plunger, and the pushing force applied to the plunger by the hydraulic oil supplied from the oil supply passage to the pressure chamber is buffered. Yes.

  In the chain tensioner as described above, the plunger is always urged in the protruding direction by the pressing of the spring. Therefore, when assembling, the plunger is pushed in and the pushed state is maintained and the housing is fixed to the engine block. There is a problem that the necessity arises and the assembly is very troublesome.

  In order to solve such problems, pin holes are formed in the outer peripheral surface of the distal end portion of the plunger and the outer peripheral surface of the distal end portion of the housing, and the pin hole of the plunger is matched with the pin hole of the housing by pushing the plunger. A chain tensioner has been proposed in which a set pin is inserted into the hole to hold the plunger in a pushed state.

  By the way, in the chain tensioner that can hold the plunger in the pushed-in state by the set pin, after the chain tensioner is attached to the engine block, the set pin is pulled out and the chain is tensioned by the plunger that moves forward by the pressing force of the spring. However, there is a case where the set pin is forgotten to be pulled out, and the situation in which the function of the chain tensioner cannot be exhibited occurs. Further, since the engine cover can be attached to the engine block even when the set pin is attached, it is impossible to confirm whether or not the chain tensioner is correctly attached.

  Furthermore, since the set pin is discarded after being pulled out, if reassembly is required after removal of the tensioner, the plunger cannot be held in a pushed state, and the assembly is difficult.

  A first technical object of the present invention is to prevent erroneous assembly of a chain tensioner that can hold the plunger in a pushed-in state.

  In addition, a second technical object of the present invention is to facilitate reassembly of the chain tensioner.

In order to solve the first and second technical problems described above, in the present invention, a cylinder chamber that opens at one end surface is formed in a housing that is attached to an engine block, and a plunger is provided in the cylinder chamber. And a spring that presses the outer side of the plunger, a pin hole penetrating in the radial direction is provided at the tip of the plunger, and a set hole is formed in the opening end of the cylinder chamber in the housing. In a chain tensioner in which a plunger is held in a pressed state by a set pin inserted from the hole into the pin hole, the engine is attached to the engine block in the initial set state in which the set pin is inserted into the set hole and the pin hole. cover interferes length Satoshi, extending in the circumferential direction on the inner periphery of the open end of the cylinder chamber A lip housing groove is formed, a ring portion that is elastically deformable in the radial direction of the register clip is housed in the clip housing groove, and the tip end portion where the pin hole of the plunger is formed is a small diameter shaft portion. A stopper surface for holding the ring portion of the register clip by holding one side surface of the clip housing groove on the cylinder chamber opening side at the base of the portion and preventing the plunger from coming off is provided, and the positional relationship between the stopper surface and the pin hole is determined by the stopper surface. However, a configuration is adopted in which the pin hole is disposed at a position offset from the set hole toward the rear end side of the plunger in a state in which the plunger holding the ring portion is held by one side face of the clip receiving groove .

Here, diameter of the ring portion a plurality of circumferential grooves which are tightened by the ring portion of the register clip on the outer periphery of the plunger in the axial direction spaced, during advancement of the plunger outside circumference of the circumferential groove When the engaging surface that engages the ring portion that stops by contacting the other side of the clip receiving groove when the plunger is retracted and prevents the plunger from retreating is provided, Since the plunger can be prevented from moving backward by the engagement of the engagement surface of the groove, it is possible to prevent the plunger from being pushed more than necessary due to the relationship of the stop position of the cam when the engine is stopped.

As described above, in the invention of this, the engine cover is set the length of the set pin to interfere with the set pin when the holding state push the plunger by inserting a set pin to the set hole and pin hole Therefore, if you forget to remove the set pin after installing the chain tensioner, the engine cover cannot interfere with the set pin and cannot be attached to the engine block. .

Also, to accommodate the elastically deformable ring portion of the register clip to clip accommodation groove, by the tip portion outer periphery of the plunger provided with clamping can stop face the ring portion at the one side of the clip accommodation groove When removing and reassembling the chain tensioner, the plunger can be held in the pushed state by the engagement of the stopper surface with the ring portion of the register clip, so that the chain tensioner can be easily reassembled.

  The pin hole is arranged at a position offset from the set hole toward the rear end side of the plunger in a state where the plunger holding the ring portion of the register clip is held by one side of the clip receiving groove and the stopper surface. In the initial setting state in which the set pin is inserted into the set hole and the pin hole, the stopper surface is arranged at a position offset from the one side surface of the ring receiving groove to the opening side of the cylinder chamber. The stopper surface does not engage with the ring portion of the register clip, and the plunger can be reliably released.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the housing 1 has a plurality of mounting pieces 2 bolted to the engine block A.

  As shown in FIG. 3, the housing 1 is formed with a cylinder chamber 3 that opens at one end surface thereof, and a plunger 4 is slidably incorporated in the cylinder chamber 3.

  The plunger 4 has a spring storage chamber 5 that opens at its rear end surface, and a spring 6 incorporated between the closed end of the spring storage chamber 5 and the closed end of the cylinder chamber 3 presses the plunger 4 outward. ing.

  The closed end wall of the cylinder chamber 3 is formed with an oil supply passage 8 communicating with the pressure chamber 7 formed in the back portion of the plunger 4, and the hydraulic oil in the pressure chamber 7 is supplied to the oil outlet side of the oil supply passage 8. A check valve 9 is provided to prevent backflow to the side.

  Between the housing 1 and the plunger 4, the 1st holding means 10 and the 2nd holding means 20 which hold | maintain the plunger 4 in the pushing state are provided.

  As shown in FIG. 4, the first holding means 10 is provided with a pair of opposed pins provided on the opening end surface of the housing 1 by providing a pin hole 12 extending in the radial direction in the small diameter shaft portion 11 provided at the distal end portion of the plunger 4. A set hole 14 is formed in the support piece 13, and a set pin 15 is inserted into the pin hole 12 from the set hole 14 to hold the plunger 4 in a pushed state.

  Here, as shown in FIG. 2 and FIG. 3, the set pin 15 has a ring portion 15a for inserting a fingertip. The set pin 15 has such a length that the engine cover B attached to the engine block A in the initial set state inserted from the set hole 14 into the pin hole 12 interferes with the ring portion 15a.

  As shown in FIG. 3 and FIG. 4, the second holding means 20 forms a clip receiving groove 21 extending in the circumferential direction on the inner periphery of the opening end of the cylinder chamber 3, and the register clip 22 in the clip receiving groove 21. A ring portion 22a that can be elastically deformed in the radial direction of the shaft, and this ring portion 22a is provided with a stopper surface 23 provided at the base of the small-diameter shaft portion 11 and a side surface 21a of the clip housing groove 21 on the cylinder chamber 3 opening side The plunger 4 is held in the pushed-in state by holding it with the.

  As shown in FIGS. 1 and 2, a pair of knobs 22 b are provided at both ends of the ring portion 22 a of the register clip 22. The pair of knobs 22b face the outside from a notch 24 provided at the opening end of the housing 1, and the ring part 22a is expanded in diameter by pressing the pair of knobs 22b from both sides.

  In the first holding means 10 and the second holding means 20 configured as described above, the ring portion 22a of the register clip 22 is shown in FIG. 6 (I) with the set pin 15 inserted from the set hole 14 into the pin hole 12. If the set pin 15 is pulled out to release the push-in holding of the plunger 4, the ring portion 22 a of the register clip 22 is formed on one side of the clip receiving groove 21. The stopper surface 23 comes into contact with the ring portion 22a and stops, and the plunger 4 cannot be released.

  Further, as shown in FIG. 6 (II), one side 21a of the clip receiving groove 21 and the stopper surface 23 connect the ring portion 22a of the register clip 22 with the set pin 15 inserted into the pin hole 12 from the set hole 14. In the state of holding, the set pin 15 may fall out of the set hole 14 and the pin hole 12.

  In order to eliminate such inconvenience, as shown in FIG. 4, the stopper surface 23 and the pin hole 12 have the following positional relationship.

  In other words, the pin hole 12 is offset from the set hole 14 to the rear end side of the plunger 4 in a state where the stopper surface 23 holds the ring portion 22a of the register clip 22 with the one side surface 21a of the clip receiving groove 21 and the plunger 4 is not detached. The positional relationship is set at the position.

  As shown in FIG. 5, a plurality of circumferential grooves 30 are formed on the outer periphery of the plunger 4 at equal intervals in the axial direction, and a tapered surface having a small diameter toward the tip of the plunger 4 on the inner periphery of each circumferential groove 30. 30a and an engagement surface 30b are provided at the small diameter end of the tapered surface 30a.

  The chain tensioner shown in the embodiment has the above-described structure. When the chain tensioner is attached to the engine block A, the set pin 15 is inserted into the pin hole 12 from the set hole 14 as shown in FIG. The mounting piece 2 of the housing 1 is bolted to the engine block A while being held in the pushed state.

  When the set pin 15 is pulled out after the chain tensioner is mounted, the plunger 4 moves outward by the pressing of the spring 6 to press the swingable chain guide (not shown), and the chain is pressed via the chain guide. The chain tension is kept constant.

  Here, if the set pin 15 is forgotten to be pulled out, the plunger 4 is held in a pushed state and cannot function as a chain tensioner. In this case, since the set pin 15 inserted into the set hole 14 and the pin hole 12 has a length that interferes with the engine cover B attached to the engine block A, the engine cover B is attached when the engine cover B is attached. It cannot be attached in contact with the set pin 15, and it is possible to know from the engine cover B that the set pin 15 has been forgotten to be removed.

  Further, in a state where the plunger 4 in which the set pin 15 is inserted into the set hole 14 and the pin hole 12 is pushed and held, the ring portion 22a of the register clip 22 is located on the rear end side of the plunger 4 from the stopper surface 23 as shown in FIG. Therefore, there is no inconvenience that the ring portion 22a of the register clip 22 is held between the one side surface 21a of the clip receiving groove 21 and the stopper surface 23 when the set pin 15 is pulled out. 4 can be reliably released.

  For this reason, erroneous assembly of the chain tensioner can be prevented, and the function as the chain tensioner can be reliably exhibited.

  After assembly of the chain tensioner as described above, hydraulic oil is supplied from the oil supply passage 8 into the pressure chamber 7 to fill the hydraulic chamber 7 with the hydraulic oil, and the pushing force applied to the plunger 4 from the chain by the hydraulic oil. Buffer.

  When the pushing force is larger than the spring force of the spring 6, the ring portion 22a of the register clip 22 abuts on the other side surface of the clip receiving groove 21, and the plunger 4 moves backward by the engagement of the engagement surface 30b with the ring portion 22a. Is blocked.

  For this reason, when the engine is stopped, the plunger 4 is prevented from moving backward due to the engagement of the ring portion 22a and the engagement surface 30b even if the chain is held in a tension state due to the relationship of the cam stop position. The chain is held in tension. Accordingly, it is possible to prevent the chain from being slackened when the engine is restarted, and to prevent the chain from fluttering and tooth skipping.

  When the chain is slackened in the chain tension adjustment state, the plunger 4 is moved outward by pressing the spring 6 and the chain is pressed through the chain guide, so that the chain slack is absorbed. .

  When the plunger 4 moves outward, the tapered surface 30a enlarges the diameter of the ring portion 22a of the register clip 22, so that the plunger 4 moves smoothly outward.

  When the chain elongates over time and the amount of movement of the plunger 4 in the outward direction increases, the rear circumferential groove 30 faces the ring portion 22a of the register clip 22, and thereafter the same operation as described above is performed. It is.

  When removing the chain tensioner due to maintenance around the engine and reassembling the chain tensioner, the knob 22b of the register clip 22 is pressed from both sides to increase the diameter of the ring portion 22a, and the plunger 4 is pushed into the plunger. 4, the stopper surface 23 of the plunger 4 is retracted from the ring portion 22a as shown in FIG. 4, and then the diameter of the ring portion 22a is reduced by releasing the knob 22b, so that the stopper surface 23 against the ring portion 22a is reduced. The chain tensioner is attached by holding the plunger 4 in the pushed-in state by the engagement.

  Thus, since the plunger 4 can be held in the pushed-in state by the register clip 22, the chain tensioner can be easily reassembled.

Partially cutaway front view showing an embodiment of a chain tensioner according to the present invention Right side view of FIG. Sectional view along line III-III in FIG. Sectional view of the plunger held in the pushed-in state by the register clip Sectional drawing which expands and shows a part of FIG. (I) and (II) are cross-sectional views in a state where inconvenience occurs due to the positional relationship between the stopper surface and the pin hole

Explanation of symbols

A Engine block B Engine cover 1 Housing 3 Cylinder chamber 4 Plunger 6 Spring 11 Small diameter shaft portion 12 Pin hole 14 Set hole 15 Set pin 21 Clip receiving groove 21a One side 22 Register clip 22a Ring portion 23 Stopper surface 30 Circumferential groove 30a Taper Surface 30b Engagement surface

Claims (1)

A cylinder chamber that opens at one end surface is formed in a housing that is attached to the engine block, and a plunger and a spring that presses the plunger outward are incorporated in the cylinder chamber, and a radial direction is provided at the distal end of the plunger. A chain having a pin hole penetrating in the housing, a set hole formed in the opening end of the cylinder chamber in the housing, and a plunger being pushed in by a set pin inserted into the pin hole from the set hole in the tensioner, the set pin, and interfere with an engine cover which is attached to the engine block in a state of being inserted into a set hole and pin hole length, extending on the inner periphery of the open end of the cylinder chamber in the circumferential direction clips An accommodation groove is formed and elastically deformed in the radial direction of the register clip in the clip accommodation groove. The tip of the plunger, in which the pin hole is formed, is used as a small-diameter shaft portion, and the base of the small-diameter shaft portion is connected to one side surface of the clip housing groove on the cylinder chamber opening side of the register clip. A stopper surface is provided for holding the ring portion to prevent the plunger from coming off, and the positional relationship between the stopper surface and the pin hole is determined so that the stopper surface holds the ring portion with one side surface of the clip receiving groove. A chain tensioner characterized in that the pin hole is disposed at a position offset from the set hole toward the rear end side of the plunger .

Images